Discharging without charging first is not a good idea. "take the load" and have "5.0Ah capacity" - what load? How was capacity tested?

No. Battery details can't be read from the car's OBD port - not even with Honda Diagnostic System (HDS). The information just isn't available.

Grid charging these batteries has been common practice for about 8 years. Most use various 350mAh LED power supplies. 2X APC-35-350 would work great.

 

Thanks for the reply. I started with 3 packs to get one good pack. Here's how I tested load and capacity.

6 cell stick, 0.9V/Cell, 50 Celcius, 5 min wait.
3 discharge > Charge cycles

100Ah 12V Deep Cycle Battery as Source.
Regenerative discharge 16A (300W max.)
sticks charged at 9A.

All good sticks between 5.0-5.3 Ah
Bad sticks, specially original pack ones, between 2.0-3.0Ah

I deep discharge the pack down to 20V using a 100W 220V tungsten filament bulb. After this the car runs fine (full assist for more than 10 secs) for about a week and then pack become unbalanced and IMA comes on.

For grid Charging I'm using Meanwell 3x RS-25-48 (48V 0.57A) and 1x LPC-20-350 (0-48V 0.35A) all in series. I made the Charger about 7-8 years ago, but I was not in my home country and the car was being used by my father.

Thanks and best regards,
Irfan.

 

I'm guessing you copied the grid charger design from 99mpg.com

1) 16A discharge to 5.4V/stick is a good way to kill them. You likely did damage while cycling.
2) 9A is too high a charge rate. 1C is preferred.
3) if you ran sticks up to 50°C before the charge was terminated, you likely did more damage.
4) A 5 minute wait is too short. 20 minutes provides a more realistic capacity.

Your testing omitted what most people's testing omits - discharge over time. This requires > 1 week of resting. You need to start over. After you've determined capacity:

Charge sticks
Let sit for 7 days.
Measure and record ALL 6 CELL VOLTAGES PER STICK
Discharge to 6V and record capacity
Once you have all 20 sticks tested, the bad ones will be the outliers - the ones with highest CELL voltages variations within the same stick and the lowest capacity.

Also, grid charging without driving the cooling fan is a good way to kill the battery. The HCH1 uses a PWM controlled fan, so you will need to provide a means of control. Alternatively, you can ground the PWM line and drive it with a 100W+ 12V power supply.

 

Hi,
Grid Charger was from older 99mpg.com website, some other URL, but its a simple 350mA constant current supply which NiMH batteries require.

No sticks seemed damaged, that were good to begin with (tested at 6A charge/6A discharge).
No stick reached 50 Celsius cutoff, maybe due to high wind near seaside and pedestal fan near the setup. Wind did destroy/corrode the charger which was replaced under warranty.

I might not go to cell level testing, but we'll see.

For Now:
Out of 60 sticks that I tested for capacity and load, 20 out of my original pack and 5 more from other 2 packs were under 4.5Ah.
Since batteries are charged between 30 and 80 percent during use, I don't want to discard the sticks that can hold charge and provide 10C discharge current. I'm looking for a way to keep them balanced during night parking either by connecting a 5W or so load on the pack or permanently connecting the grid charger within the car (maybe with an inverter) and timer to top up every hour for 15 mins or so. Fan should not be required but supplying PWM to it won't be a problem.

Thanks and best regards,
Irfan

 

Your pursuit is folly.

Capacity is the least important characteristic. Do the testing as I prescribed, or you're just going to go in circles never finding a solution.

 

Then how about replacing (or adding) a lithium polymer set. 40S should be the same nominal voltage with LiHV taking a maximum of 174V. I know that LiHV require CC-CV for charging but if I can determine that the maximum charging voltage is under 174V, it can work.

 

It will work perfectly until the car rams 50A into it at 211.2V. The IPU might even contain the fireball long enough for you to escape.

 

211.2 would be for 132 cells on HCH2. For 120 cells shouldn't it be lower?
Also if used in parallel with NiMH, most of 50A would go to NiMH. Otherwise Lithium Polymer BMS could be used.

 

The fire would occur at 192V instead.

 

Hello.

I have a 2005 Civic IMA which is now at 197k km. The IMA battery was replaced in 2011 at about 110k km and has worked flawlesly (never seen a recal) until last month. I was driving down a pretty steep 15km hill. When I reached the bottom engine and IMA lights came on and the charge gauge showed 1 bar (even though that the battery was completely full considering the long downhill) and tried to recalibrate, but never succeeded. The OBD2 codes were P1600 and P1433 at the time.

1)
I read tons of threads around this forum and decided that I will try to fix every stick separately. I disassembled the pack and on first cycle discharged every stick to 1V/cell, and in second cycle to 0.8V/cell (at appropriate current low current of course). Most of the sticks were then able to be charged to more than 6000mAh. Those that weren't reaching at least 6000mAh of charge, I then cycled them to 0.6V/cell. After that all sticks were able to be charged at least 6000mAh.

I assembled the pack and put it back in the car, but the problem wasn't fixed. I was then getting codes P1600, P1446 and P1443 (not always the same, sometimes only 2 of those), so I decided to try with grid charging.

2)
I built myself a dumb grid charger using two APC-35-350 in series (with appropriate fuse and diode protection). I grid charged for about 14h (with proper cooling) and the peak voltage that the pack reached was 171V. Then it started slowly decreasing to 170.1V. I unpluged the grid charger and let the pack rest for about a day. Then I plugged it on grid charger again for about 6h and the voltage raised to 170.1V where it stayed for a few hours. I put the pack in the car then, but the problem was exactly the same (same codes being thrown, I tried resetting the computer by unplugging 12V battery several times).

When I start the car it initially starts charging, but when the 1 bar shows it simply stops (appears that IMA system gets completely disabled at the car never tries to charge the battery until you restart the engine) and throws OBD codes. Otherwise the car is working normally, 12V battery is also being charged all the time.


I kinda ran out of ideas, how could I fix this? I don't understand why exactly the same codes are being thrown after a grid charging. When I worked on every stick separately, none of them showed any weird signs. Yes, some of the sticks self-discharge faster, but considering that the time between being unplugged from grid charger and trying the pack in the car is less than 30min, I can't imagine that the pack could already go out of balance.
It also seems that I also got rid of voltage depression in those sticks that had it (some of them held more than 1000mAh between 1V and 0.8V/cell).


I would really appreciate any idea, what else can I try. I have already spent more than one month working on this and kinda irritated by it already.